That is good data, Dennis.
I changed my plugs this afternoon (I had a
set of RX-7 plugs so that is what I used) and will fly tomorrow. I will
check the stability of my manifold pressure then. I installed a plastic
fuel filter in the line a while back. I have two manifold pressure lines
from the intake manifold. Each of them is “T”ed into the lawnmower
fuel filter and then they separate at a “T” and go to the two
inputs to the EC-2 controller. If it is not stable, I will try your idea
of a partial blockage of the filter inlet.
So with 95% the hiccup is not totally eliminated.
How often would you say you now get a hiccup?
Bill B
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Dennis Havarlah
Sent: Tuesday, September 04, 2012
11:00 AM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re:
Intermittent hiccup
I've been using iridium plugs in my Renesis for 300
hrs. I am using the iridium plugs that come from the factory. When
I changed them at 250 hrs I did not notice any change in performance! I
use regular car gas with ethanol and very seldom do I use 100 LL.
I had a hiccup every so often and could not eliminate
it until I put damper chambers in my manifold lines. I used the
small plastic fuel filters for lawnmowers (Purolator F21124). This eliminated
at least 95 % of the hiccup and my manifold pressure is very
steady. With the dampers my manifold pressure varies about 0.1
in hg up or down in cruise. Without the damper it would
vary as much as 0.3 to 0.4 in hg in cruise. I
plugged the inlet of the filter with JB and drilled a hole about 0.032 inch in
diameter through the epoxy. Check your manifold pressure and see if it is
stable.
----- Original Message -----
Sent: Tuesday, September
04, 2012 1:29 AM
Subject: [FlyRotary] Re:
Intermittent hiccup
Yup, I suspect SAG.
I go through plugs very quickly.. like 25hrs. No cleaning will help
as the electrode is worn out. You can milk them to 100 hrs but its not
really worth it. SAG gets really bad by 75 hrs. The platinum onea
last an extra hour or two. Have not tried the iridium. Always
change plugs before a long trip. Also, they come out much easier after
only 25 or so hours.
--
David Leonard
Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net
On Mon, Sep 3, 2012 at 8:46 PM, Bill
Bradburry <bbradburry@bellsouth.net> wrote:
Has anyone ever noticed a hiccup associated with sparkplug
SAG? I have a hiccup that is occurring at random intervals from seconds
to several minutes. Sometimes it is pretty mild and sometimes it shakes
the plane! I also seem to be down in power and I am beginning to suspect
plug SAG. I have 38 hours with the Iridium plugs plus a lot of time over
the years of running the engine before flight. I had a couple instances
of flooding which required that I take the plugs out and sandblast them to get
them to fire. Just drying them out didn’t work.
Thoughts??
Bill B